The present invention relates generally to apparatus and methods for blocking the rotatable shaft of the rotatable assembly of machinery during shipment thereof. More particularly, the invention relates to such apparatus and methods for large rotatable assemblies supported by a roller bearing.
Manufacturers of large machinery often must ship this machinery long distances by land or sea. The rotatable assemblies of such machinery must be locked in place during shipment to prevent damage to the bearings during shipment. The conventional practice of blocking movements of the rotatable assemblies calls for placing a brace across the drive end of the rotatable shaft. While such bracing is effective to lock the shaft in the axial direction and the circumferential direction, this blocking method appears to work satisfactorily only when the bearings for the shaft consist of a single roller bearing supporting the drive end of the shaft and a ball bearing supporting the opposite end, i.e., the non-drive end, of the shaft.
However, when the bearings for the rotatable assembly consist of a ball bearing and a roller bearing at the non-drive end of the shaft, conventional bracing of the shaft assembly fails to prevent the tendency of the rotatable assembly to vibrate through the roller bearing components, and this can result in damage to the roller bearing. The ball bearing on this end is locked in the axial direction by the conventional brace. But simply controlling axial movement cannot prevent the roller bearing from movements in the radial direction. Moreover, rigidly blocking the shaft in the radial direction can cause bearing damage.
Another conventional method for blocking the shaft, relies on a cone that is bolted so as to lift the shaft from the bearings to remove all load from the bearings. However, this method cannot prevent the small motions of the rollers that causes false-brinelling, which damages the roller bearing.